{"id":10799,"date":"2013-05-14T16:39:23","date_gmt":"2013-05-14T16:39:23","guid":{"rendered":"http:\/\/cornellsailing.com\/2013\/05\/aventura-4-an-unpainted-tin-can-for-all-seasons-2\/"},"modified":"2015-06-30T17:18:29","modified_gmt":"2015-06-30T17:18:29","slug":"aventura-4-an-unpainted-tin-can-for-all-seasons","status":"publish","type":"post","link":"https:\/\/cornellsailing.com\/de\/2013\/05\/aventura-4-an-unpainted-tin-can-for-all-seasons\/","title":{"rendered":"Aventura IV: An unpainted tin can for all seasons"},"content":{"rendered":"
\"\"<\/div>\n

The first report on the plans for my new boat<\/a> has generated much interest, and I had several questions. I\u2019ll deal with the most frequently asked ones first.<\/p>\n

Why\u00a0 aluminium?<\/em><\/h3>\n

The first Aventura\u00a0<\/em> was a strong well built GRP boat which survived a three hour grounding on a\u00a0 reef on the Caicos Bank with only superficial scratches. She served me\u00a0 perfectly well during my first circumnavigation but for my next boat I decided\u00a0 to go for steel mainly because, once again, I was planning to explore out of\u00a0 the way places and believed that a metal boat was better suited for such a purpose.<\/p>\n

It didn\u2019t take me long to realise that while metal was\u00a0 indeed a good choice, the maintenance of a steel hull was a real nightmare and that I should have listened to my friend Erick Bouteleux and go for aluminium,\u00a0 as he had done himself.<\/p>\n

So when the time came for No. 3, the decision had already\u00a0 been taken. In the following 13 years my aluminium OVNI 43<\/a> took me all over\u00a0 the world, including Antarctica and Alaska, and I became totally converted to\u00a0 this wonderful material.<\/p>\n

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Aventura III, my aluminium OVNI 43 took me all over the world<\/p><\/div>\n

One of the greatest advantages of aluminium over any other\u00a0 boat building material is that aluminium spontaneously forms a thin but effective oxide layer that prevents further oxidation. Aluminium oxide is\u00a0 impermeable and, unlike the oxide layers on many other metals, it adheres\u00a0 strongly to the parent metal. If damaged, this oxide layer repairs itself\u00a0 immediately.<\/p>\n

I must point out that my hull, and any other hull, is not made of\u00a0 pure aluminium, but an alloy. Those used in boat construction contain magnesium,\u00a0 such alloys having excellent durability in sea water.<\/p>\n

Why an unpainted hull? <\/em><\/h3>\n

As on my previous boat, my main priority\u00a0 was not only a strong boat but also a functional one, and, in my view, nothing\u00a0 can be more functional and maintenance free than an unpainted hull.<\/p>\n

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While in Antarctica, colliding with bits of ice was practically unavoidable<\/p><\/div>\n

One of the\u00a0 great advantages of an unpainted aluminium hull, especially for those of us who\u00a0 do not buy a boat to sit in a marina but to be out there sailing, is that you\u00a0 can forget about gleaming topsides. As most owners will surely agree, they can\u00a0 be such a worry when confronted with rough docks, barnacle covered pilings, or being\u00a0 boarded by uncaring officials who often come alongside banging into your hull with\u00a0 their launch without any fenders.<\/p>\n

While in Antarctica, colliding with bits of\u00a0 ice was practically unavoidable, and we ended up without any scratches to speak\u00a0 of whereas friends of ours on two fibreglass boats fared much worse.<\/p>\n

Why centreboard?<\/em><\/h3>\n

One of the first questions everyone asks me<\/a>\u00a0 is how safe it is to sail on a boat without a keel.<\/p>\n

Having sailed twice across\u00a0 the Drake Passage to Antarctica, both times on a centreboard boat, and having\u00a0 experienced on at least two occasions winds around 60 knots, with swell to\u00a0 match, was a perfect opportunity to test, and put to rest, any doubts about\u00a0 stability.<\/p>\n

Thanks to an internal lead ballast of 3.5 tons and a displacement of\u00a0 9 tons, my previous Aventura<\/em> was as\u00a0stable as any more traditionally designed cruising boat. I am sure that the\u00a0 next Aventura<\/em> will be no different. I\u00a0 need to point out that both the previous Aventura\u00a0<\/em> and her successor have an integral centreboard, which means that the board can\u00a0 be fully retracted into the hull.<\/p>\n

There are many advantages to a centreboard,\u00a0 besides shallow draft. The main role of the board is to provide lift when\u00a0 sailing close-hauled and reduce leeway when reaching. With the board fully down\u00a0 my previous boat drew eight feet and, when sailed properly, it could point as\u00a0 high, or almost as high, as most cruising boats.<\/p>\n

What I mean by sailed properly\u00a0 is that when hard on the wind sail trim is critical, a good speed must be kept\u00a0 up and heeling too much must be avoided or you end up making a lot of leeway. With\u00a0 a draft of ten feet with the board down, the new Aventura <\/em>should perform even better.<\/p>\n

There is a certain technique in sailing a\u00a0 centreboarder efficiently, not just on the wind but off the wind as well. This\u00a0 is when the centreboard becomes a true asset as it allows you to reduce the\u00a0 wetted surface. Also, the ability to lift the board gradually as the apparent\u00a0 wind goes past 135\u00b0, and then continue lifting it up to the point when the\u00a0 board is fully retracted, is a great advantage as the risk of broaching is\u00a0 virtually eliminated. The absence of a keel to act as a pivot in a potential\u00a0 broaching situation means that the boat does not tend to round up when, in a\u00a0 similar situation, a keeled boat would do just that. It is a feature that I\u00a0 have blessed on many occasions, and that had allowed me to continue keeping the\u00a0 spinnaker up longer than I would have done otherwise.<\/p>\n

The board was normally\u00a0 retracted when motoring in calm waters and the reduction in wetted surface\u00a0 provided an extra 0.3 to 0.5 knots of speed.<\/p>\n

Why do\u00a0 I consider shallow draft to be so important?<\/em><\/h3>\n
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Aventura III beached<\/p><\/div>\n

In all surveys dealing with the subject of\u00a0 ideal draft there was a consensus that whereas a fixed keel may be best suited\u00a0 for ocean passages, when cruising having a shallow draft boat is not only ideal\u00a0 for exploring places that other boats cannot reach, but also safe because it\u00a0 allows you to tuck into a protected spot if needing shelter in an emergency.<\/p>\n

Indeed, one of the main reasons for\u00a0 choosing a centreboarder is to increase my cruising options, and having a boat\u00a0 whose draft can be reduced instantly is a huge advantage. The fact that most\u00a0 aluminium centreboard boats have a flat bottom means that with the board fully\u00a0 up the boat can dry out on any beach, tidal bay or estuary. When the tide runs\u00a0 out, the boat settles down comfortably, and, as the height of the stern\u00a0 platform is less than three feet above the dried out surface, access aboard is\u00a0 very easy with the aid of the swimming ladder. We have dried out on many\u00a0 occasions, whether to put on a quick coat of antifouling between tides while\u00a0 cruising the Chilean canals, or to access a shallow bay in Alaska so we could\u00a0 watch grizzly bears fishing for salmon.<\/p>\n

One other advantage of having a centreboard,\u00a0 that is nothing more than an aluminium plate, is that one can use it as a\u00a0 sounding board when entering an unfamiliar shallow anchorage. It is a technique\u00a0 I learned from an old friend and taught me a new meaning for the term \u2018sounding\u00a0 board\u2019.<\/p>\n

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